Horse Pasture Management

In the book Gulliver’s Travels, author Jonathan Swift states, “…whoever could make two ears of corn, or two blades of grass, to grow upon a spot of ground where only one grew before, would deserve better of mankind, and do more essential service to his country, than the whole race of politicians put together.” Few horse owners would disagree with that statement, as nutritious pastures are a requisite for growing healthy horses.

In the wake of the 2001 outbreak of equine foal and embryo deaths known as mare reproductive loss syndrome (MRLS), proper pasture development and maintenance have received increased attention. The need to determine a cause for the devastation visited upon Kentucky and adjoining states by MRLS led many researchers to look towards pasture anomalies for clues. Agronomists, individuals who study the science and economics of crop production and the management of farmland, were called to assist in finding answers.

One in particular, Roger Allman of The Farm Clinic, an independent research firm in West Lafayette, Indiana with a branch in Lexington, Kentucky, was able to provide statistics from past years to compare to those drawn from soil samples taken in 2001. Information he supplied was used to disprove some theories and put an increased focus on others. Many questions remain, but Mr. Allman hopes that the continued collaborative efforts by researchers across many disciplines may shed more light upon the causes and possible prevention of MRLS.

The specter of the unknown assailant has definitely caused horse farm owners to more closely examine their pastures. Mr. Allman stated that many people who contact him for assistance fall into one of two categories–those who overdo and those who do nothing out of fear of doing the wrong thing. In both cases, pastures can be helped by first determining the current soil properties and then treating the pastures appropriately to encourage suitable growth. Mr. Allman is in a position to advise his clients, as he has a long family tradition of interest in agronomy and years of experience in the field (literally and figuratively) upon which to draw. He is the second generation of his family to be involved with The Farm Clinic and currently owns a part of the business with Richard Shoemaker, the man who had been his father’s partner.

The Farm Clinic was founded in 1936 by Dr. C. M. Long, an intrepid professor at Purdue University, who advocated the need to test soils to determine a pasture’s requirements for specific fertilization and treatments. Agronomists at that time disagreed with Dr. Long and felt that there was no real science involved in the process. This break from tradition caused Dr. Long to leave the security of university life for a private practice where he could advise his clients and help them to produce crops with higher yields and farm animals that gained weight rapidly on their pastures. Mr. Allman’s father, Marshall, gained his master’s degree in soil fertility from Purdue and joined Dr. Long after World War II. He brought the first horse farms into the business in the 1950s, beginning with Castleton Farm and the farms of Lee Eaton and University of Kentucky basketball coaching legend Adolph Rupp. Mr. Shoemaker and the senior Mr. Allman bought out Dr. Long’s interest when he retired. They brought other people into the company, including Roger who had also graduated from Purdue with a bachelor’s degree in agronomy. Today, the company employs ten people in West Lafayette and three in Lexington. The number and soil diversity of the horse farms relying upon the advice offered by the firm, over 500 Thoroughbred farms in 19 states and five foreign countries, is evidence of the company’s success.

Mr. Allman stated, “Horse farm managers are always looking for an edge that will help them produce a better yearling or a faster racehorse. I think many of our clients see our services as just that– something extra that might help to put them over the top.”

That something extra is a very involved process that begins with a consultation to determine the farm’s needs. A detailed map of the farm including each pasture and paddock is drawn and a member of The Farm Clinic staff begins the process of collecting numerous soil samples from every area. This requires walking through each paddock with a tool to remove plugs of soil, which are then deposited in carefully marked bags. Copious notes are taken on every pasture’s condition so that the soil analysis can be compared to a visual assessment before recommendations are made. Mr.Allman explained, “We take a number of samples – at least one every two acres. We also look at the pasture’s use. Horses are not as uniform a crop as corn or wheat. They graze some areas more heavily than others. The value of our crop is such that spending the time to do a thorough examination of each paddock and field is well worth the effort.”

The soil samples are driven to the company’s laboratory in Indiana where each is tested for calcium, magnesium, zinc, iron, copper, organic matter, and sulfur. The results are compared to those from other farms in the immediate area and to past data to determine if the levels are in acceptable ranges or if they need to be supplemented by applications of fertilizer or lime to bring the field into optimum ranges. Carefully drafted and color-coded maps are developed from the test results so that the farm manager can easily visualize the needs of each paddock. Because the soil samples are taken from marked areas in each field and paddock, specific recommendations can be made for areas within a field so that lime or fertilizer can be applied only to the areas that need attention. According to Mr. Allman, “This helps to avoid overtreating areas that may already be at optimum levels.”

“I am in a unique position when I advise a farm manager,” he explained. “The Farm Clinic does not sell fertilizer or lime; we tell our clients what we think their pastures require so they can make the decisions for themselves. I may tell a farm manager that his pastures are fine and need nothing added to them this year, which is just as valuable as advice to the contrary. The owner will avoid spending money over treating his pastures.”

When fertilization is deemed necessary, Mr. Allman strongly advises his clients to apply it in the fall as that is the best time to promote root growth and plant thickening. Fertilizer applied in the spring does more to help top growth that can be disadvantageous to the horse and does little to strengthen the plant itself. Lime, which changes the pH of the soil, can be applied at any time so long as horses are removed from the field until rain has washed the lime into the ground.

The application of fertilizer and lime on paddocks devoted to horses is designed in a somewhat different fashion today, thanks in part to studies done by Dr. Joe Pagan, the president of Kentucky Equine Research, an equine nutrition and exercise physiology company based in Versailles, Kentucky. Mr. Allman recounted, “Research done by Dr. Pagan and his staff clearly indicates that rapid growth rates correlate with bone problems such as physitis and osteochondritis dissecans (OCD). This makes our number one concern providing young growing horses with a pasture that is nutritionally balanced as opposed to one that will promote rapid weight gain.”

Other types of pasture maintenance such as mowing and weed control also figure into the mix. Contrary to how it may appear, a short “golf course” pasture, while aesthetically pleasing to humans, may not be best for horses. Mr. Allman maintained that “a short pasture will be less resistant to drought and horse traffic. A healthy pasture for horses should be mowed every 14 days or so to a height of six to eight inches during rapid spring growth and less often during the drier summer months. This keeps grass growing a good leaf and not concentrating effort on growing a seed head. Some people believe that allowing the plant to grow seed and then mowing that off will help to reseed pastures. This is not the best way to keep pastures lush. It is much better to purchase seed and plant it properly on a regular basis.”

Choosing the correct seed for pastures is also important. Different areas of the world may require special types of grasses, but, for the most part, Mr. Allman suggests a combination of Kentucky bluegrass, orchard grass, perennial ryegrass, and white clover. Even with this type of careful planting, weeds will make an appearance. Mr. Allman believes that, “Quality horse pastures are not large lawns. Some weeds and diversity are acceptable.” Other weeds, however, are not. Mowing on a regular basis will help to control some weeds, but others will need to be chemically treated. Mr. Allman suggests that the whole pasture be treated as opposed to spot spraying. He said, “Horses should be removed from the pasture whenever any toxic chemical is sprayed on a plant. While it might cost more to chemically treat the entire pasture, if the horses have to be removed anyway, why not get all the bad weeds at one time?”

The Farm Clinic also makes recommendations for other types of pasture maintenance including aerating, chain harrowing, and resting paddocks. Like fertilizing and seeding, these types of pasture treatments are best done at certain times of the year. And, like the maps provided to indicate soil needs, charts are furnished that indicate these times.

While some farms have massive pastures available for their animals, others have more limited spaces. The smallest farm that utilizes the company’s services contains only three acres, but, Mr. Allman laughed, “They are three of the most intensely managed acres on the planet.” He continued, “Some farms have 20 horses on 20 acres. Others may have 20 horses on 200 acres. Our goal is to help the farm manager devise the best program to grow the best horses for the area available to them.”

In some cases, such as the three-acre farm, soil tests are done quite frequently, and in others the tests are done every two years, which is the norm. While many of The Farm Clinic’s clients are large farms with substantial financial backing, Mr. Allman claims that every farm can benefit from soil testing. He likens soil to a bank account from which plants and animals draw necessary nutrients. The account needs to be regularly inspected and, when needed, replenished. A firm like The Farm Clinic can perform those tests, or farm managers can pull their own soil samples and have them evaluated by their local feed store or county extension agency. The important factor is that the samples be taken on a regular basis and evaluated properly.

Many farms have been clients of The Farm Clinic for decades, and it is the data from these farms that proved invaluable during the MRLS outbreak when theories abounded as to the cause of the foal deaths. One such theory was that calcium and phosphorus ratios were out of balance. Mr. Allman was able to use over 50 years of data to show that, while this balance had been affected by climatic conditions, it was no greater a difference than had been seen many times in the past.

Mr. Allman, like many researchers investigating the baffling syndrome, has concerns about the number of Eastern tent caterpillars seen last year and, to a lesser extent, this year. He explained, “Research has shown that just two of these caterpillars per square inch over an acre can produce an estimated 110 pounds of frass, as their manure is called. We may discover that there is a correlation between the frass and the foal deaths. Insects and fowl produce excrement that contains uric acid. If uric acid is found to be a contributing factor, then it may change the way we look at not just tent caterpillars, but also other insects and waterfowl, like geese and ducks. There is still a great amount of research that needs to be done before we can point a finger at any one thing.”

Mr. Allman believes the search for answers to MRLS will concern a great many horse owners and scientists for quite some time. He takes his role in helping to find those answers quite seriously. “I look at all the pastures I test as being my pastures, and I want what is hurting the horses out of them,” he said.